Semiconductor devices and method of manufacutring the same

ABSTRACT

A semiconductor device includes a first transistor in a first region and a second transistor in a second region. The first transistor includes: a first nanowire, a first gate electrode, a first gate dielectric layer, a first source/drain region, and an inner-insulating spacer. The first nanowire has a first channel region. The first gate electrode surrounds the first nanowire. The first gate dielectric layer is between the first nanowire and the first gate electrode. The first source/drain region is connected to an edge of the first nanowire. The inner-insulating spacer is between the first gate dielectric layer and the first source/drain region. The second transistor includes a second nanowire, a second gate electrode, a second gate dielectric layer, and a second source/drain region. The second nanowire has a second channel region. The second gate electrode surrounds the second nanowire. The second gate dielectric layer is between the second nanowire and the second gate electrode. The second source/drain region is connected to an edge of the second nanowire.

CROSS-REFERENCE TO RELATED APPLICATION

This U.S. non-provisional patent application claims priority under 35U.S.C. § 119 to Korean Patent Application No. 10-2016-0172883, filed onDec. 16, 2016 in the Korean Intellectual Property Office (KIPO), thedisclosure of which is incorporated herein in its entirety by reference.

BACKGROUND 1. Technical Field

The present disclosure relates to a semiconductor device and a method ofmanufacturing the same. More particularly, the present disclosurerelates to a semiconductor device including nanowire transistors andmethods of manufacturing the same.

2. Discussion of the Related Art

Electronic devices have become smaller, lighter and thinner. As aresult, demand for high integration of semiconductor devices hasincreased. Due to downscaling of semiconductor devices, a short channeleffect is generated in transistors, and thus, a problem has arisen inthat semiconductor devices have become less reliable. Thus, asemiconductor device with a multi-gate structure, such as agate-all-around type nanowire transistor, has been proposed to reducethe short channel effect in transistors.

SUMMARY

The concepts described herein provide a semiconductor device including ananowire transistor configured to have an optimum performance.

The concepts described herein also provide methods of manufacturing asemiconductor device including a nanowire transistor configured to havean optimum performance.

According to an aspect of the present disclosure, a semiconductor deviceincludes a first transistor and a second transistor. The firsttransistor is in a first region of a substrate and the second transistoris in a second region of the substrate. The first transistor includes afirst nanowire, a first gate electrode, a first gate dielectric layer, afirst source/drain region, and an inner-insulating spacer. The firstnanowire has a first channel region. The first gate electrode surroundsthe first nanowire. The first gate dielectric layer is between the firstnanowire and the first gate electrode. The first source/drain region isconnected to an edge of the first nanowire. The inner-insulating spaceris between the first gate dielectric layer and the first source/drainregion. The second transistor includes a second nanowire, a second gateelectrode, a second gate dielectric layer, and a second source/drainregion. The second nanowire has a second channel region. The second gateelectrode surrounds the second nanowire. The second gate dielectriclayer is between the second nanowire and the second gate electrode. Thesecond source/drain region is connected to an edge of the secondnanowire.

According to another aspect of the present disclosure, a semiconductordevice includes a first transistor and a second transistor. The firsttransistor is in a first region of a substrate and the second transistoris in a second region of the substrate. The first transistor includesmultiple first nanowires, a first gate electrode, a first gatedielectric layer, a first source/drain region, and an inner-insulatingspacer. The first nanowires have multiple first channel regions. Thefirst gate electrode surrounds the first nanowires. The first gatedielectric layer is between the first nanowires and the first gateelectrode. The first source/drain region is connected to an edge of thefirst nanowires. An inner-insulating spacer is between the first gatedielectric layer and the first source/drain region. The secondtransistor includes multiple second nanowires, a second gate electrode,a second gate dielectric layer, and a second source/drain region. Thesecond nanowires have multiple second channel regions. The second gateelectrode surrounds the second nanowires. The second gate dielectriclayer is between the second nanowires and the second gate electrode. Thesecond source/drain region is connected to an edge of the secondnanowires.

According to another aspect of the present disclosure, a semiconductordevice includes a substrate with a first region and a second region; afirst transistor in the first region of the substrate and comprising afirst nanowire, a first gate electrode surrounding the first nanowire, afirst gate dielectric layer, a first source region, a first drainregion, and an inner-insulating spacer, and a second transistor in thesecond region of the substrate comprising a second nanowire, a secondgate electrode surrounding the second nanowire, a second gate dielectriclayer, a second source region and a second drain region. The first gatedielectric layer is provided between the first nanowire and the firstgate electrode, and between the inner-insulating spacer and the firstgate electrode. The inner-insulating spacer maintains a space betweenthe first gate dielectric layer and the first source region and thefirst drain region. The second gate dielectric layer is provided betweenthe second nanowire and the second gate electrode, between the secondsource region and the second gate electrode, and between the seconddrain region and the second gate electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure will be more clearly understoodfrom the following detailed description taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a top view of a semiconductor device according to an exampleembodiment of the present disclosure;

FIG. 2 is a cross-sectional view taken along lines IIA-IIA′ and IIB-IIB′of FIG. 1.

FIG. 3 is a cross-sectional view taken along lines IIIA-IIIA′ andIIIB-IIIB′ of FIG. 1.

FIG. 4 is a cross-sectional view taken along lines IVA-IVA′ and IVB-IVB′of FIG. 1.

FIG. 5 is a cross-sectional view of a semiconductor device according toan example embodiment of the present disclosure;

FIG. 6 is a cross-sectional view of a semiconductor device according toan example embodiment of the present disclosure;

FIG. 7 is a top view of a semiconductor device according to an exampleembodiment of the present disclosure;

FIG. 8 is a cross-sectional view taken along lines VIIIA-VIIIA′ andVIIIB-VIIIB′ of FIG. 7.

FIG. 9 is a cross-sectional view taken along lines IXA-IXA′ and IXB-IXB′of FIG. 7.

FIG. 10 is a cross-sectional view taken along lines XA-XA′ and IIB-IIB′of FIG. 7.

FIG. 11 is a cross-sectional view of a semiconductor device according toan example embodiment of the present disclosure;

FIG. 12 is a cross-sectional view of a semiconductor device according toan example embodiment of the present disclosure;

FIG. 13 is a cross-sectional view illustrating a method of manufacturinga semiconductor device according to an example embodiment of the presentdisclosure.

FIG. 14 is a cross-sectional view illustrating a method of manufacturinga semiconductor device according to an example embodiment of the presentdisclosure.

FIG. 15 is a cross-sectional view illustrating a method of manufacturinga semiconductor device according to an example embodiment of the presentdisclosure.

FIG. 16 is a cross-sectional view illustrating a method of manufacturinga semiconductor device according to an example embodiment of the presentdisclosure.

FIG. 17 is a cross-sectional view illustrating a method of manufacturinga semiconductor device according to an example embodiment of the presentdisclosure.

FIG. 18 is a cross-sectional view illustrating a method of manufacturinga semiconductor device according to an example embodiment of the presentdisclosure.

FIG. 19 is a cross-sectional view illustrating a method of manufacturinga semiconductor device according to an example embodiment of the presentdisclosure.

FIG. 20 is a cross-sectional view illustrating a method of manufacturinga semiconductor device according to an example embodiment of the presentdisclosure.

FIG. 21 is a cross-sectional view illustrating a method of manufacturinga semiconductor device according to an example embodiment of the presentdisclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, example embodiments of the present disclosure will bedescribed in detail with reference to the accompanying drawings.

FIG. 1 is a top view of a semiconductor device 100 according to anexample embodiment of the present disclosure. FIG. 2 is across-sectional view taken along lines IIA-IIA′ and IIB-IIB′ of FIG. 1.FIG. 3 is a cross-sectional view taken along lines IIIA-IIIA′ andIIIB-IIIB′ of FIG. 1. FIG. 4 is a cross-sectional view taken along linesIVA-IVA′ and IVB-IVB′ of FIG. 1.

Referring to FIGS. 1 through 4, a substrate 110 of the semiconductordevice 100 includes a first region I and a second region II. An activeregion (not shown) may be defined by an isolation layer 112 in each ofthe first region I and the second region II. A first transistor TR1 maybe formed in the active region of the first region I and a secondtransistor TR2 may be formed in the active region of the second regionII. In an example embodiment, the first transistor TR1 may be an n-typemetal-oxide-semiconductor (NMOS) transistor, and the second transistorTR2 may be a p-type metal-oxide-semiconductor (PMOS) transistor.

In an example embodiment, the substrate 110 may be a silicon substrate.In an example embodiment, the substrate 110 may constitute at least onedevice selected from a large scale integration (LSI), a logic circuit,an image sensor such as a CMOS imaging sensor (CIS), a memory devicesuch as a flash memory, a dynamic random access memory (DRAM), a staticrandom access memory (SRAM), an electrically erasable programmableread-only memory (EEPROM), a phase change RAM (PRAM), a magnetic RAM(MRAM), or a resistive RAM (RRAM), or a micro-electro-mechanical system(MEMS).

The first transistor TR1 may include a first nanowire 120A, a first gateelectrode 130A, a first gate dielectric layer 132A, a pair of firstsource/drain regions 140A, and an inner-insulating spacer 170. In FIG.2, the first gate electrode 130A is shown above and below the firstnanowire 120A. Similarly, the first gate dielectric layer 132A is shownabove and below the first nanowire 120A and around all four sides of thefirst gate electrode 130A below the first nanowire 120A and around threeof the four sides of the first gate electrode 130A above the firstnanowire 120A. Accordingly, as shown in FIG. 2, the first gate electrode130A and the first gate dielectric layer 132A surround the firstnanowire 120A in parallel planes in the YZ directions.

The first nanowire 120A may include a first channel region (not shown)of the first transistor TR1. In an example embodiment, the firstnanowire 120A may include a Group IV semiconductor, a Group II-IVcompound semiconductor, or a Group III-V compound semiconductor. Forexample, the first nanowire 120A may include Si, Ge, SiGe, InGaAs, InAs,GaSb, InSb, or a combination of these materials. Channel regions are notdetailed relative to the first nanowire 120A in FIGS. 1-12 (or othernanowires), but correspond to channel layers 120P described with respectto FIGS. 13-18 and generally provide for channeling energy (electrons)between the first source/drain regions 140A. The first nanowire 120Agenerally has a dimension (size) much greater in the X direction than inthe YZ plan, even in a ratio of 1000 or greater.

The first gate electrode 130A may include a doped polysilicon, a metal,or a combination of these materials. For example, the first gateelectrode 130A may include Al, Cu, Ti, Ta, W, Mo, TaN, NiSi, CoSi, TiN,WN, TiAl, TiAlN, TaCN, TaC, TaSiN, or a combination of these materials,but the first gate electrode 130A is not limited thereto.

The first gate dielectric layer 132A may include a silicon oxide film, asilicon oxynitride film, a high-k film having a dielectric constantgreater than that of silicon oxide film, or a combination of thesematerials. For example, the high-k film that may be used as the firstgate dielectric layer 132A may include HfO₂, HfSiO, HfSiON, HfTaO,HfTiO, HfZrO, zirconium oxide, aluminum oxide, an HfO₂—Al₂O₃ alloy, or acombination of these materials, but the first gate dielectric layer 132a and the high-k film are not limited thereto.

The pair of the first source/drain regions 140A may be formed on thesubstrate 110. The pair of the first source/drain regions 140A mayextend to both edges of the first nanowire 120A along a direction (a Zdirection) perpendicular to a main surface of the substrate 110. In anexample embodiment, the pair of the first source/drain regions 140A mayinclude a doped SiGe film, a doped Ge film, a doped SiC film or a dopedInGaAs film, but the pair of the first source/drain regions 140 a arenot limited thereto. The pair of the first source/drain regions 140A maybe a semiconductor layer re-grown using an epitaxy process from thesubstrate 110 and the first nanowire 120A, and the pair of the firstsource/drain regions 140A may include a different material from thesubstrate 110 and the first nanowire 120A.

The pair of the first source/drain regions 140A may have an upper levelhigher than that of the first nanowire 120A. In an example embodiment, aportion of the pair of the first source/drain regions 140A may be adoped region functioning as a source/drain region for the firsttransistor TR1. For example, when a portion of the pair of the firstsource/drain regions 140A, from a bottom surface to a certain height ofthe pair of the first source/drain regions 140A, is highly doped withdopant ions, the portion may be a dopant region functioning as asource/drain region for the first transistor TR1. Unlike this, when aportion of the pair of the first source/drain regions 140A, from acentral region to a certain height is highly doped with a dopant, theportion may be a dopant region functioning as a source/drain region forthe first transistor TR1. In another example embodiment, whole of thepair of the first source/drain region 140A may be a dopant regionfunctioning as source/drain region for the first transistor TR1.

A first external insulating spacer 150A may cover a sidewall orsidewalls of the first gate electrode 130A on the opposite side of thefirst gate dielectric layer 132A from the first gate electrode 130A.That is, the first external insulating spacer 150A may surround a sideor sides of the first gate electrode 130A in parallel planes in the XYdirection above the first nanowire 120A. The same is true for the secondexternal insulating spacer 150B described herein. Additionally, bothedges of the first nanowire 120A adjacent to the pair of the firstsource/drain regions 140A may also be covered by the first externalinsulating spacer 150A.

The pair of the first source/drain regions 140A and a part of the firstexternal insulating spacer 150A may be covered by a first insulatinglayer 160A. A first contact 162A may be connected to the pair of thefirst source/drain regions 140A through the first insulating layer 160A.A first metal silicide layer 164A may be formed between the firstcontact 162A and the pair of the first source/drain regions 140A.

An inner-insulating spacer 170 may be formed between the substrate 110and the first nanowire 120A. The inner-insulating spacer 170 may bearranged between the first gate electrode 130A and the pair of the firstsource/drain regions 140A. The first gate dielectric layer 132A may bearranged between the inner-insulating spacer 170 and the first gateelectrode 130A. In FIG. 2, the inner-insulating spacer 170 is shown onone side (i.e., below) but not the other (i.e., above) of the firstnanowire 120A. Accordingly, while the first gate electrode 130A andfirst gate dielectric layer 132A are shown on both sides (i.e., belowand above) of the first nanowire 120A in FIG. 2, the inner-insulatingspacer 170 is shown only below. That is, the first gate dielectric layer132A may extend from a surface of the first nanowire 120A to a surfaceof a sidewall of the inner-insulating spacer 170 so that, between anupper surface of the substrate 110 and the (lower surface in FIG. 2 ofthe) first nanowire 120A, the first gate dielectric layer 132A isinterposed between the first gate electrode 130A and theinner-insulating spacer 170. Accordingly, the pair of the firstsource/drain regions 140A may contact the inner-insulating spacer 170,and may not contact the first gate dielectric layer 132A.

The inner-insulating spacer 170 may include a different material fromthe first gate dielectric layer 132A. In an example embodiment, theinner-insulating spacer 170 may include a material having a dielectricconstant less than a material that constitutes the first gate dielectriclayer 132A. In another example embodiment, the inner-insulating spacer170 may include a Group IV semiconductor oxide, a Group II-IV compoundsemiconductor oxide, or a Group III-V compound semiconductor oxide, anoxide such as a silicon oxide, or a silicon oxynitride, a siliconnitride, or a combination of these materials.

The first external insulating spacer 150A and the inner-insulatingspacer 170 may be respectively arranged at locations perpendicularlyoverlapping each other and at different levels from each other along adirection (a Z direction) perpendicular to the main surface of thesubstrate 110. In an example embodiment, the inner-insulating spacer 170may include a material different from a material that constitutes thefirst external insulating spacer 150A. In an example embodiment, theinner-insulating spacer 170 may include a material having a dielectricconstant less than that of a material that constitutes the firstexternal insulating spacer 150A.

The second transistor TR2 may include a second nanowire 120B, a secondgate electrode 130B, a second gate dielectric layer 132B, and a pair ofsecond source/drain regions 140B. In FIG. 2, the second gate electrode130B is shown above and below the second nanowire 120B. Similarly, thesecond gate dielectric layer 132B is shown above and below the secondnanowire 120B and around all four sides of the second gate electrode130B below the second nanowire 120B and around three of the four sidesof the second gate electrode 130B above the second nanowire 120B.Accordingly, as shown in FIG. 2, the second gate electrode 130B and thesecond gate dielectric layer 132B surround the second nanowire 120B inparallel planes in the YZ directions.

The second nanowire 120B may include a second channel region (not shown)of the second transistor TR2. Channel regions are not detailed relativeto the second nanowire 120B in FIGS. 1-12 (or other nanowires), butcorrespond to channel layers 120P described with respect to FIGS. 13-18and generally provide for channeling energy (holes) between the secondsource/drain regions 140B. The second nanowire 120B generally has adimension (size) much greater in the X direction than in the YZ plan,even in a ratio of 1000 or greater.

The second gate electrode 130B and the second gate dielectric layer 132Bmay have similar characteristics described with respect to the firstgate electrode 130A and the first gate dielectric layer 132A. Forexample, the second gate electrode 130B may include a doped polysilicon,a metal, or a combination of these materials, and the second gatedielectric layer 132B mat include a silicon oxide film, a siliconoxynitride film, a high-k film having a dielectric constant greater thanthat of silicon oxide film, or a combination of these materials.

In an example embodiment, the second gate electrode 130B and the firstgate electrode 130A may include same material, and the second gatedielectric layer 132B and the first gate dielectric layer 132A mayinclude same material. Unlike this, the second gate electrode 130B andthe first gate electrode 130A may include different materials from eachother, and the second gate dielectric layer 132B and the first gatedielectric layer 132A may include different materials from each other.

The pair of the second source/drain regions 140B may be formed on thesubstrate 110. The pair of the second source/drain regions 140B mayextend to both edges of the second nanowire 120B along a direction (a Zdirection) perpendicular to a main surface of the substrate 110. Thepair of the second source/drain regions 140B may be a semiconductorlayer re-grown using an epitaxy process from the substrate 110 and thesecond nanowire 120B, and the pair of the second source/drain regions140B may include a different material from the substrate 110 and thesecond nanowire 120B. In an example embodiment, the pair of the secondsource/drain regions 140B may include a doped SiGe film, a doped Gefilm, a doped SiC film, or a doped InGaAs film, but the pair of thesecond source/drain regions 140B are not limited thereto.

In an example embodiment, the pair of the second source/drain regions140B may include different material from the pair of the firstsource/drain regions 140A. For example, the pair of the firstsource/drain regions 140A may include SiC and the pair of the secondsource/drain regions 140B may include SiGe or Ge.

A second external insulating spacer 150B, a second insulating layer160B, a second contact 162B, and a second metal silicide layer 164Brespectively may have similar characteristics to the first externalinsulating spacer 150A, the first insulating layer 160A, the firstcontact 162A, and the first metal silicide layer 164A. In an exampleembodiment, the second external insulating spacer 150B, the secondinsulating layer 160B, the second contact 162B, and the second metalsilicide layer 164B respectively may be formed in the same processes forforming the first external insulating spacer 150A, the first insulatinglayer 160A, the first contact 162A, and the first metal silicide layer164A. In another example embodiment, the second external insulatingspacer 150B may be formed in a process different from a process forforming the first external insulating spacer 150A. Also, the secondinsulating layer 160B may be formed in a process different from aprocess for forming the first insulating layer 160A.

Unlike the first transistor TR1, the second transistor TR2 may notinclude the inner-insulating spacer 170, and the inner-insulating spacer170 may not be arranged between the substrate 110 and the secondnanowire 120B. As depicted in FIG. 2, the second gate dielectric layer132B may be arranged between the second gate electrode 130B and the pairof the second source/drain regions 140B. That is, the second gatedielectric layer 132B may extend from between the substrate 110 and thesecond nanowire 120B to between the second gate electrode 130B and thepair of the second source/drain regions 140B. The pair of the secondsource/drain regions 140B may contact the second gate dielectric layer132B.

The second external insulating spacer 150B and a part of the second gateelectrode 130B may be respectively arranged at locations perpendicularlyoverlapping each other and at different levels from each other along adirection (a Z direction) perpendicular to the main surface of substrate110.

As depicted in FIG. 2, the inner-insulating spacer 170 may be formedbetween the first gate electrode 130A and the pair of the firstsource/drain regions 140A, whereas the inner-insulating spacer 170 maynot be formed between the second gate electrode 130B and the pair of thesecond source/drain regions 140B. Accordingly, the first transistor TR1and second transistor TR2 are constructed differently, and whereas thesecond gate dielectric layer 132B contacts the second source/drainregion 140B on either side of the second gate electrode 130B, the firstgate dielectric layer 132A is spaced apart by the inner-insulatingspacer 170 from the first source/drain region 140A on either side of thefirst gate electrode 130A.

Since the inner-insulating spacer 170 is formed between the first gateelectrode 130A and the pair of the first source/drain regions 140A, aseparation distance between the first gate electrode 130A and the pairof the first source/drain regions 140A may be increased. Accordingly, inthe first transistor TR1, the generation of a parasitic capacitancebetween the first gate electrode 130A and the pair of the firstsource/drain regions 140A may be reduced, and the first transistor TR1may shows a rapid operation speed. In particular, when the firsttransistor TR1 is an NMOS transistor, the performance of the NMOStransistor may be increased due to the reduction of the parasiticcapacitance.

Since the inner-insulating spacer 170 is not formed between the secondgate electrode 130B and the pair of the second source/drain regions140B, the pair of the second source/drain regions 140B may have a highcrystal quality. If the inner-insulating spacer 170 is arranged onexposed surfaces of a pair of the second source/drain recess regions140RB (refer to FIG. 15) in a process for growing the pair of the secondsource/drain regions 140B, multiple stacking faults or dislocations maygenerate in the pair of the second source/drain regions 140B. Thecrystal quality of the pair of the second source/drain regions 140B maynot be high due to the stacking faults or dislocations, and the pair ofthe second source/drain regions 140B may be difficult to function as astressor that applies a compressive strain to the second nanowire 120B.

However, since inner-insulating spacer 170 is not formed between thesecond gate electrode 130B and the pair of the second source/drainregions 140B, the generation of the stacking faults or dislocations inthe pair of the second source/drain regions 140B may be suppressed, andthus, the pair of the second source/drain regions 140B may have a highcrystal quality. Accordingly, the pair of the second source/drainregions 140B may function as a stressor that applies a compressivestrain to the second nanowire 120B, and thus, the second transistor TR2may show a rapid operation speed. In particular, if the secondtransistor TR2 is a PMOS transistor, the performance of the PMOStransistor may be increased by the high crystal quality of the pair ofthe second source/drain regions 140B.

In the semiconductor device 100 according to an example embodimentdescribed above, the first transistor TR1, for example, an NMOStransistor may provide a high performance due to the reduction of aparasitic capacitance generated by the inner-insulating spacer 170, andthe second transistor TR2, for example, a PMOS transistor may provide ahigh performance due to the high crystal quality of the pair of thesecond source/drain regions 140B. Accordingly, the semiconductor device100 may have an optimum performance.

FIG. 5 is a cross-sectional view of a semiconductor device 100Baccording to an example embodiment of the present disclosure. FIG. 5shows cross-sections corresponding to the cross-sections taken along theline IIA-IIA′ and the line IIB-IIB′ of FIG. 1. In FIG. 5, like referencenumerals are used to indicate elements that are identical to theelements of FIGS. 1 through 4.

Referring to FIG. 5, the semiconductor device 100A may further include afirst channel separation region 180A between the substrate 110 and thefirst gate electrode 130A and a second channel separation region 180Bbetween the substrate 110 and the second gate electrode 130B. The firstchannel separation region 180A may include conductive type dopant ionsopposite to the conductive type dopant included in the pair of the firstsource/drain regions 140A, and the second channel separation region 180Bmay include a conductive type dopant opposite to the conductive typedopant included in the pair of the second source/drain regions 140B. Thefirst channel separation region 180A and second channel separationregion 180B may prevent the formation of channels on an upper surface ofthe substrate 110 facing bottom surfaces of the first gate electrode130A and second gate electrode 130B. For example, a channel path may beformed from a lower portion of one of the pair of the first source/drainregions 140A to a lower portion of the other one of the pair of thefirst source/drain regions 140A through the first nanowire 120A, andaccordingly, a short channel effect may be prevented.

FIG. 6 is a cross-sectional view of a semiconductor device 100Baccording to an example embodiment of the present disclosure. FIG. 6shows cross-sections corresponding to the cross-sections taken along theline IIA-IIA′ and the line IIB-IIB′ of FIG. 1. In FIG. 6, like referencenumerals are used to indicate elements that are identical to theelements of FIGS. 1 through 5.

Referring to FIG. 6, the semiconductor device 100B may include mayfurther include a first buffer layer 190A between the substrate 110 andthe first gate electrode 130A and a second buffer layer 190B between thesubstrate 110 and the second gate electrode 130B.

The first buffer layer 190A and second buffer layer 190B may include amaterial having a lattice constant greater than that of a material usedto form the substrate 110. In an example embodiment, the substrate 110may include Si and the first buffer layer 190A and second buffer layer190B may include GaAs, InP, InAlAs, or a combination of these materials.In an example embodiment, the first buffer layer 190A and second bufferlayer 190B may be a single layer or a multilayer. For example, the firstbuffer layer 190A and second buffer layer 190B may have a multi-layeredstructure in which a first layer including GaAs and a second layerincluding InP or InAlAs are sequentially stacked on the substrate 110.

In an example embodiment, the pair of the first source/drain regions140A may include a material different from the first nanowire 120A, andthe pair of the second source/drain regions 140B may include a materialdifferent from the second nanowire 120B. Accordingly, the first nanowire120A and second nanowire 120B may include a strained channel. As aresult, carrier mobility of the first transistor TR1 and secondtransistor TR2 that include the first nanowire 120A and second nanowire120B may be increased.

For example, in the second transistor TR2, the second nanowire 120B mayinclude Ge, and the pair of the second source/drain regions 140B mayinclude doped SiGe. In the first transistor TR1, the first nanowire 120Amay include InGaAs, and the pair of the first source/drain regions 140Amay include doped InGaAs. A composition ratio of In and Ga of InGaAsincluded in the first nanowire 120A may be different from thecomposition ratio of In and Ga of InGaAs included in the pair of thefirst source/drain regions 140A. However, the materials and thecomposition ratios of first nanowire 120A and second nanowire 120B andthe pair of the first source/drain region 140A and second source/drainregion 140B are not limited thereto.

FIG. 7 is a top view of a semiconductor device 200 according to anexample embodiment of the present disclosure. FIG. 8 is across-sectional view taken along lines VIIIA-VIIIA′ and VIIIB-VIIIB′ ofFIG. 7. FIG. 9 is a cross-sectional view taken along lines IXA-IXA′ andIXB-IXB′ of FIG. 7. FIG. 10 is a cross-sectional view taken along linesXA-XA′ and IIB-IIB′ of FIG. 7. In FIGS. 7 through 10, like referencenumerals are used to indicate elements that are identical to theelements of FIGS. 1 through 6.

Referring to FIGS. 7 through 10, the semiconductor device 200 mayinclude a first transistor TR1 formed in a first region I of a substrate110 and a second transistor TR2 formed in a second region II of thesubstrate 110.

The first transistor TR1 may include multiple first nanowires 120A1,120A2 and 120A3, a first gate electrode 230A, a first gate dielectriclayer 232A, a pair of first source/drain regions 140A, andinner-insulating spacers 170. The first gate electrode 230A surroundsthe first nanowires 120A1, 120A2 and 120A3 in parallel planes in the YZdirections. The first gate dielectric layer 232A is arranged between thefirst gate electrode 230A and the first nanowires 120A1, 120A2 and120A3. The inner-insulating spacers 170 are arranged between the pair ofthe first source/drain regions 140A and the first gate electrode 230A.

The second transistor TR2 may include multiple second nanowires 120B1,120B2 and 120B3, a second gate electrode 230B, a second gate dielectriclayer 232B, and a pair of second source/drain regions 140B. The secondgate electrode 230B surrounds the second nanowires 120B1, 120B2 and120B3 in parallel planes in the YZ directions. The second gatedielectric layer 232B is arranged between the second gate electrode 230Band the second nanowires 120B1, 120B2 and 120B3.

In the first transistor TR1, the first nanowires 120A1, 120A2 and 120A3respectively locate on different levels from each other from an uppersurface of the substrate 110, and distances to each of the firstnanowires 120A1, 120A2 and 120A3 from the upper surface of the substrate110 are different from each other. The first nanowires 120A1, 120A2 and120A3 respectively may include multiple first channel regions (notshown). The first gate electrode 230A may be formed to surround at leasta part of each of the first nanowires 120A1, 120A2 and 120A3 in parallelplanes in the YZ directions. The first gate electrode 230A may includefirst sub-gate electrodes 230A1, 230A2, and 230A3 respectively formed ina space between the substrate 110 and the first nanowires 120A1, 120A2and 120A3. The first gate dielectric layer 232A may be arranged betweenthe first gate electrode 230A and the first nanowires 120A1, 120A2 and120A3.

The inner-insulating spacers 170 respectively may be formed between thefirst sub-gate electrodes 230A1, 230A2, and 230A3 and the pair of thefirst source/drain regions 140A between the substrate 110 and the firstnanowires 120A1, 120A2 and 120A3. The pair of the first source/drainregions 140A may not contact the first gate dielectric layer 232A, andthe inner-insulating spacers 170 may include a different material fromthe first gate dielectric layer 232A.

In the second transistor TR2, the second nanowires 120B1, 120B2 and120B3 respectively locate on different levels from each other from anupper surface of the substrate 110, and distances to each of the secondnanowires 120B1, 120B2 and 120B3 from the upper surface of the substrate110 are different from each other. The second nanowires 120B1, 120B2 and120B3 respectively may include multiple second channel regions (notshown). The second gate electrode 230B may be formed to surround atleast a part of each of the second nanowires 120B1, 120B2 and 120B3 inparallel planes in the YZ directions. The second gate electrode 230B mayinclude second sub-gate electrodes 230B1, 230B2, and 230B3 respectivelyformed in a space between the substrate 110 and the second nanowires120B1, 120B2 and 120B3. The second gate dielectric layer 232B may bearranged between the second gate electrode 230B and the second nanowires120B1, 120B2 and 120B3. The second gate dielectric layer 132B may extendto a space between pair of the second source/drain regions 140B and thesecond sub-gate electrodes 230B1, 230B2, and 230B3.

As depicted in FIG. 8, the inner-insulating spacers 170 are formed onlybetween the first sub-gate electrodes 230A1, 230A2, and 230A3 and thepair of the first source/drain regions 140A, and may not be formedbetween the second sub-gate electrodes 230B1, 230B2, and 230B3 and thepair of the second source/drain regions 140B. Accordingly, a separationdistance between the pair of the first source/drain regions 140A and thefirst sub-gate electrodes 230A1, 230A2, and 230A3 may be greater than aseparation distance between the pair of the second source/drain regions140B and the second sub-gate electrodes 230B1, 230B2, and 230B3. In anexample embodiment, when the first transistor TR1 is an NMOS transistor,since the separation distance between the pair of the first source/drainregions 140A and the first sub-gate electrodes 230A1, 230A2, and 230A3is relatively large, the generation of parasitic capacitance between thepair of the first source/drain regions 140A and the first sub-gateelectrodes 230A1, 230A2, and 230A3 may be reduced. Accordingly, the NMOStransistor may have a rapid operation speed.

However, the inner-insulating spacers 170 are not formed between thesecond sub-gate electrodes 230B1, 230B2, and 230B3 and the pair of thesecond source/drain regions 140B. Thus, the pair of the secondsource/drain regions 140B may have a high crystal quality. If multipleinner-insulating spacers 170 are arranged on exposed surfaces of pair ofthe second source/drain recess regions 140RB (refer to FIG. 15) in aprocess for growing the pair of the second source/drain regions 140B,multiple stacking faults or dislocations may be generated in the pair ofthe second source/drain regions 140B due to the inner-insulating spacers170 including an insulating material. The crystal quality of the pair ofthe second source/drain regions 140B may not be high due to the stackingfaults or dislocations, and it may be difficult for the pair of thesecond source/drain regions 140B to function as a stressor that appliesstress to the second nanowire 120B.

However, the inner-insulating spacer 170 is not formed between thesecond gate electrode 130B and the pair of the second source/drainregions 140B. The pair of the second source/drain regions 140B may beformed using first through third sacrifice layers 240P1, 240P2, 240P3(refer to FIG. 16) and the second nanowires 120B1, 120B2 and 120B3 asseed layers. The generation of stacking faults or dislocations in thepair of the second source/drain regions 140B is suppressed, and thus,the pair of the second source/drain regions 140B may have high crystalquality. Accordingly, the pair of the second source/drain regions 140Bmay function as a stressor that applies stress to the second nanowires120B1, 120B2 and 120B3, and thus, the second transistor TR2 may have ahigh operation speed. In particular, when the second transistor TR2 is aPMOS transistor, the performance of the PMOS transistor may be increasedby the high crystal quality of the pair of the second source/drainregions 140B.

In the semiconductor device 200 according to an example embodiment, thefirst transistor TR1, that is, an NMOS transistor may provide a highperformance due to the reduction of a parasitic capacitance by theinner-insulating spacer 170, and the second transistor TR2, that is, aPMOS transistor may provide a high performance by a high crystal qualityof the pair of the second source/drain regions 140B. Accordingly, thesemiconductor device 200 may provide a high performance.

FIG. 11 is a cross-sectional view of a semiconductor device 200Aaccording to an example embodiment of the present disclosure. FIG. 11shows cross-sections corresponding to the cross-sections taken along theline VIIIA-VIIIA′ and the line VIIIB-VIIIB′ of FIG. 7. In FIG. 11, likereference numerals are used to indicate elements that are identical tothe elements of FIGS. 1 through 10.

Referring to FIG. 11, each of the inner-insulating spacers 170 may havea sidewall protruding in a direction towards the first sub-gateelectrodes 230A1, 230A2, and 230A3. The first gate dielectric layer 232Amay be formed to have a conformal thickness on the sidewall of each ofthe inner-insulating spacers 170. The first sub-gate electrodes 230A1,230A2, and 230A3, which are arranged on the sidewalls of theinner-insulating spacers 170 with the first gate dielectric layer 232Ainterposed therebetween, may have sidewalls concaved towards an innerside thereof. As depicted in FIG. 11, the first sub-gate electrodes230A1, 230A2, and 230A3 respectively may include tail portions 230AT onan upper edge and a lower edge thereof conforming a shape of thesidewall of the inner-insulating spacers 170.

The profile of the sidewalls of the inner-insulating spacers 170 isreduced or exaggerated for convenience of explanation, and thus, a slopeof the sidewalls of the inner-insulating spacers 170 may vary asnecessary.

In an example process for forming the inner-insulating spacers 170,after alternately and sequentially forming a sacrifice layer 240P (referto FIG. 13) and a channel layer 120P (refer to FIG. 13), firstsource/drain recess regions 140RA (refer to FIG. 17) are formed byetching portions of the sacrifice layer 240P and the channel layer 120P.As a result, a sidewall of the sacrifice layer 240P may be exposed onsidewalls of the first source/drain recess regions 140RA. At this point,parts of the exposed sidewall of the sacrifice layer 240P may beselectively removed using an etch condition in which the sacrifice layer240P has an etch selectivity with respect to the channel layer 120P (forexample, an etching rate of the sacrifice layer 240P is relativelyhigher than that of the channel layer 120P). Parts of the sacrificelayer 240P removed according to the etch condition may be larger in acentral region than an upper edge or a lower edge. Thus, as depicted inFIG. 11, the inner-insulating spacers 170 each having protruded sidewallmay be formed by performing an etch-back process after forming aninsulating layer (not shown) on locations where the sacrifice layer 240Pis removed. However, the inner-insulating spacers 170 and other featuresdescribed above are not limited to the above descriptions. Theinner-insulating spacers 170 may be formed by performing a thermaloxidation process on the exposed sidewall of the sacrifice layer 240P.

FIG. 12 is a cross-sectional view of a semiconductor device 200Baccording to an example embodiment of the present disclosure. FIG. 12shows cross-sections corresponding to the cross-sections taken along theline VIIIA-VIIIA′ and the line VIIIB-VIIIB′ of FIG. 7. In FIG. 12, likereference numerals are used to indicate elements that are identical tothe elements of FIGS. 1 through 11.

Referring to FIG. 12, the pair of the second source/drain regions 140Bmay include multiple protrusion portions 140BP facing the secondsub-gate electrodes 230B1, 230B2, and 230B3, and a second gatedielectric layer 232B may be arranged between the protrusion portions140BP and the second sub-gate electrodes 230B1, 230B2, and 230B3.

In an example process for forming the pair of the second source/drainregions 140B, after alternately and sequentially forming the sacrificelayer 240P (refer to FIG. 13) and the channel layer 120P (refer to FIG.13), pair of second source/drain recess regions 140RB (refer to FIG. 15)are formed by etching portions of the sacrifice layer 240P and thechannel layer 120P. As a result, a sidewall of the sacrifice layer 240Pmay be exposed on sidewalls of the pair of the second source/drainrecess regions 140RB. At this point, parts of the exposed sidewall ofthe sacrifice layer 240P may be selectively removed using an etchcondition in which the sacrifice layer 240P has an etch selectivity withrespect to the channel layer 120P (for example, an etching rate of thesacrifice layer 240P is relatively higher than that of the channel layer120P). Parts of the sacrifice layer 240P removed according to the etchcondition may be larger in a central region than an upper edge or alower edge. Afterwards, the pair of the second source/drain regions 140Bthat fill inner sides of the pair of the second source/drain recessregions 140RB may be formed using an epitaxy process.

In example embodiments, damage to the sidewall of the sacrifice layer240P may occur or a crystal quality of the sacrifice layer 240P may bepartly degraded in the etching process for forming the pair of thesecond source/drain recess regions 140RB. However, the part of thesidewall of the sacrifice layer 240P where the crystal quality isdegraded may be removed by a selective removal process. Afterwards, thepair of the second source/drain regions 140B having a high crystalquality may be formed using the sacrifice layer 240P and the channellayer 120P exposed on the sidewalls of the pair of the secondsource/drain recess regions 140RB as seed layers.

In another example embodiment, a sidewall area of the pair of the secondsource/drain recess regions 140RB may be increased by the selectiveremoval process, and accordingly, relatively large areas of thesacrifice layer 240P and the channel layer 120P may be exposed on theinner sidewalls of the pair of the second source/drain recess regions140RB. Thus, the pair of the second source/drain regions 140B having ahigh crystal quality may be formed using the exposed areas of thesacrifice layer 240P and the channel layer 120P as seed layers. However,the pair of the second source/drain regions 140B are not limitedthereto.

It should be understood that the sidewall profiles of the pair of thesecond source/drain regions 140B and the protrusion portion 140BPdepicted in FIG. 12 are simplified or exaggerated for convenience ofexplanation.

In the semiconductor device 200 according to the example embodimentsdescribed above, the first transistor TR1, for example, an NMOStransistor may provide a high performance due to a parasitic capacitancein the inner-insulating spacers 170, and the second transistor TR2, forexample, a PMOS transistor may provide a high performance by a highcrystal quality of the pair of the second source/drain regions 140B.Accordingly, the semiconductor device 200 may provide a highperformance.

FIGS. 13 through 21 are cross-sectional views illustrating a method ofmanufacturing a semiconductor device 200 according to an exampleembodiment of the present disclosure. In FIGS. 13 through 21,cross-sections corresponding to the cross-sections taken along lineVIII-VIII′ of FIG. 7 are depicted according to a sequence ofmanufacturing processes.

Referring to FIG. 13, the first channel separation region 180A andsecond channel separation region 180B may be formed by implanting dopantions at a high concentration into the substrate 110 from the mainsurface of the substrate 110. The substrate 110 may include a firstregion I and a second region II. The first region I may be an NMOStransistor region, and the second region II may be a PMOS transistorregion.

Afterwards, the sacrifice layer 240P and the channel layer 120P arealternately and sequentially formed on the substrate 110. The sacrificelayer 240P and the channel layer 120P may be formed using an epitaxyprocess. The sacrifice layer 240P may include first through thirdsacrifice layers 240P1, 240P2, and 240P3, and the channel layer 120P mayinclude first through third channel layers 120P1, 120P2, and 120P3.

In example embodiments, the sacrifice layer 240P and the channel layer120P may include materials having an etch selectivity with respect toeach other. For example, the sacrifice layer 240P and the channel layer120P respectively may include a monolayer of a Group IV semiconductor, aGroup II-IV compound semiconductor, or a Group III-V compoundsemiconductor, and the sacrifice layer 240P and the channel layer 120Pmay include different materials from each other. In an exampleembodiment, the sacrifice layer 240P may include SiGe, and the channellayer 120P may include single-crystal silicon.

In example embodiments, the epitaxy process may be vapor-phase epitaxy(VPE) process, a chemical vapor deposition (CVD) process such as anultra-high vacuum chemical vapor deposition (UHV-CVD) process, amolecular beam epitaxy process, or a combination of these processes. Inthe epitaxy process, a liquid or vapor precursor may be used as aprecursor required for forming the sacrifice layer 240P and the channellayer 120P.

Referring to FIG. 14, after forming a mask pattern (not shown) extendingwith a predetermined length in a first direction (an X direction) on thechannel layer 120P, a first trench T1 may be formed by etching the firstthrough third channel layers 120P1, 120P2, and 120P3, the first throughthird sacrifice layers 240P1, 240P2, and 240P3, the first channelseparation region 180A and second channel separation region 180B, andthe substrate 110 using the mask pattern as an etch mask.

Afterwards, an inner side of the trench T1 is filled with an insulatingmaterial, an isolation layer 112 may be formed by planarizing an uppersurface of the insulating material. An active region AC may be definedon the substrate 110 by the isolation layer 112, and the active regionAC may include a well into which predetermined type dopant ions areimplanted.

Afterwards, in the first region I and second region II, first dummy gatestructure 260A and second dummy gate structure 260B may be formed on astack structure of the first through third sacrifice layers 240P1,240P2, and 240P3 and the first through third channel layers 120P1,120P2, and 120P3 and first dummy gate structure 260A and second dummygate structure 260B and on the isolation layer 112. The first dummy gatestructure 260A and second dummy gate structure 260B respectively mayinclude first etch-stop layer 262A and second etch-stop layer 262B,first dummy gate electrode 264A and second dummy gate electrode 264B,first capping layer 266A and second capping layer 266B, and firstexternal insulating spacer 150A and second external insulating spacer150B.

For example, the first dummy gate structure 260A and second dummy gatestructure 260B may include polysilicon, the first capping layer 266A andsecond capping layer 266B may include a silicon nitride film. The firstetch-stop layer 262A and second etch-stop layer 262B may include amaterial having an etch selectivity with respect to the first dummy gatestructure 269A and second dummy gate structure 260B. For example, thefirst etch-stop layer 262A and second etch-stop layer 262B may includeat least one film selected from a thermal oxide film, a silicon oxidefilm, and a silicon nitride film. The first external insulating spacer150A and second external insulating spacer 150B may include siliconoxide, silicon oxynitride, or silicon nitride, but are not limitedthereto.

Referring to FIG. 15, a first protection layer 272 covering the firstdummy gate structure 260A and the first through third channel layers120P1, 120P2, and 120P3 may be formed in the first region I. In thesecond region II, the pair of the second source/drain recess regions140RB may be formed by etching parts of the first through third channellayers 120P1, 120P2, and 120P3, the first through third sacrifice layers240P1, 240P2, and 240P3, the second channel separation region 180B, andthe substrate 110 using the second dummy gate structure 260B as an etchmask.

The pair of the second source/drain recess regions 140RB may have adepth larger than that of the second channel separation region 180B inthe substrate 110. Since the pair of the second source/drain recessregions 140RB are formed, parts of the first through third channellayers 120P1, 120P2, and 120P3 are removed, and the second nanowires120B1, 120B2 and 120B3 may be formed from the remaining parts of thefirst through third channel layers 120P1, 120P2, and 120P3.

Referring to FIG. 16, after growing a single-crystal film from thesubstrate 110, the second nanowires 120B1, 120B2 and 120B3, and thefirst through third sacrifice layers 240P1, 240P2, and 240P3 in the pairof the second source/drain recess regions 140RB, the pair of the secondsource/drain regions 140B that fill the pair of the second source/drainrecess regions 140RB may be formed.

In an epitaxy process for growing the pair of the second source/drainregions 140B, all of the substrate 110, the second nanowires 120B1,120B2 and 120B3, and the first through third sacrifice layers 240P1,240P2, and 240P3 that are exposed on the sidewalls of the pair of thesecond source/drain recess regions 140RB respectively may besingle-crystal semiconductor layers. Accordingly, the generation ofdislocations or stacking faults by lattice mismatch in the growingprocess of the pair of the second source/drain regions 140B may beprevented, and thus, the pair of the second source/drain regions 140Bmay provide a high crystal quality.

Generally, a seed layer or a template for an epitaxy process may includea single-crystal semiconductor layer having a discontinuous interface ormultiple single-crystal semiconductor surfaces separately arranged by aninsulating layer. When this happens, there is a high possibility ofgenerating dislocations or stacking faults in the single-crystalsemiconductor layer grown on the seed layer or the template. Thesingle-crystal semiconductor layer including the dislocations orstacking faults may hardly function as a stressor that appliescompressive strain or tension stress to a channel region.

However, according to the method of manufacturing the semiconductordevice 200 according to the present disclosure, all of the substrate110, the second nanowires 120B1, 120B2 and 120B3, and the first throughthird sacrifice layers 240P1, 240P2, and 240P3 that are exposed on thesidewalls of the pair of the second source/drain recess regions 140RBmay be single-crystal semiconductor layers. In particular, for example,when compared to a case where the insulating layer (or inner-insulatingspacers) is exposed on the sidewalls of the pair of the secondsource/drain recess regions 140RB, the generation of dislocations orstacking faults in the pair of the second source/drain regions 140Bgrowing in the pair of the second source/drain recess regions 140RB maybe prevented, and thus, the pair of the second source/drain regions 140Bmay provide a high crystal quality.

In example embodiments, the second source/drain regions 140B may includemultiple layers. For example, the second source/drain regions 140B mayinclude a multi-layer structure in which first and second layersincluding SiGe may be formed, but the first and second layersrespectively may have different contents of Si and Ge, or a multi-layerstructure in which first through third layers including SiGe may beformed, but the first through third layers respectively may havedifferent contents of Si and Ge.

Afterwards, the first protection layer 272 may be removed.

Referring to FIG. 17, a second protection layer 274 may be formed in thesecond region II. The pair of the first source/drain recess regions140RA may be formed by etching parts of the first through third channellayers 120P1, 120P2, and 120P3, the first through third sacrifice layers240P1, 240P2, and 240P3, the first channel separation region 180A, andthe substrate 110 on both sides of the first dummy gate structure 260Ausing the first dummy gate structure 260A in the first region I as anetch mask.

Referring to FIG. 18, sacrifice recess regions 240R may be formed bylaterally etching parts of the first through third sacrifice layers240P1, 240P2, and 240P3 exposed by the pair of the first source/drainrecess regions 140RA.

In example embodiments, an etch condition may exist in which firstthrough third sacrifice layers 240P1, 240P2, and 240P3 have a high etchrate with respect to the first through third channel layers 120P1,120P2, and 120P3. The sacrifice recess regions 240R may be formed byremoving a predetermined thickness of the first through third sacrificelayers 240P1, 240P2, and 240P3 exposed on the sidewalls of the pair ofthe first source/drain recess regions 140RA based on the etch condition.As depicted in FIG. 18, the sacrifice recess regions 240R may have avertical sidewall profile, and unlike this, as depicted in FIG. 11, mayhave a concave sidewall profile.

Referring to FIG. 19, after filling inner sides of the sacrifice recessregions 240R by forming a conforming insulating layer (not shown) onsidewalls of the pair of the first source/drain recess regions 140RA,the inner-insulating spacers 170 may be only remain in the inner side ofthe sacrifice recess regions 240R using an etch-back process.

Referring to FIG. 20, the pair of the first source/drain regions 140Athat fill the pair of the first source/drain recess regions 140RA may beformed in the pair of the first source/drain recess regions 140RA byre-growing single-crystal layers from the substrate 110 and the firstnanowires 120A1, 120A2 and 120A3.

Referring to FIG. 21, the second protection layer 274 (refer to FIG. 20)may be removed.

Afterwards, after forming insulating layers 160A and 160B on theisolation layer 112, the first dummy gate structure 260A and seconddummy gate structure 260B (refer to FIG. 20), and the pair of the firstsource/drain region 140A and second source/drain region 140B, upperparts of the insulating layers 160A and 160B are removed using aplanarizing process of an etch-back process, and as a result, the firstdummy gate structure 260A and second dummy gate structure 260B may beexposed to the outside. Afterwards, the first dummy gate structure 260Aand second dummy gate structure 260B are removed to have first gatespace GSA and second gate space GSB between the pair of externalinsulating spacers 150A and 150B. The first nanowires 120A1, 120A2 and120A3 may be exposed through the first gate space GSA, and the secondnanowires 120B1, 120B2 and 120B3 may be exposed through the second gatespace GSB.

Afterwards, the first gate space GSA and second gate space GSB mayextend to an upper surface of the substrate 110 by selectively removingparts of the first through third sacrifice layers 240P1, 240P2, and240P3 exposed through the first gate space GSA and second gate spaceGSB.

For example, first sub-gate spaces GSA1, GSA2, and GSA3 may be formed onlocations where the first through third sacrifice layers 240P1, 240P2,and 240P3 are removed in the first region I, and second sub-gate spacesGSB1, GSB2, and GSB3 may be formed on locations where the first throughthird sacrifice layers 240P1, 240P2, and 240P3 are removed in the secondregion II.

Referring to FIG. 20 and FIG. 8, the first gate dielectric layer 232Aand second gate dielectric layer 232B respectively are formed onsurfaces exposed in the first gate space GSA and second gate space GSB.That is, the first gate dielectric layer 232A and second gate dielectriclayer 232B respectively are formed on exposed surfaces of each of thefirst nanowires 120A1, 120A2 and 120A3, the second nanowires 120B1,120B2 and 120B3, and the first channel separation region 180A and secondchannel separation region 180B, exposed surfaces of the inner-insulatingspacers 170, and exposed surfaces of the pair of the first externalinsulating spacer 150A and second external insulating spacer 150B.Afterwards, the first gate electrode 230A and second gate electrode 230Bthat fill the first space GSA and second gate space GSB respectively maybe formed on the first gate dielectric layer 232A and second gatedielectric layer 232B.

In the semiconductor device 200 manufactured according to the methoddescribed above, the first transistor TR1, for example, an NMOStransistor may provide a high performance since a parasitic capacitancegenerated in the inner-insulating spacers 170 is reduced, and the secondtransistor TR2 may provide a high performance by a high crystal qualityof the pair of the second source/drain regions 140B.

Example embodiments of the present disclosure have been described withreference to the accompanying drawings. In the current specification,the example embodiments are described by using specific terms. However,it should be understood that the terms are used to explain the technicalscope of the concepts described herein are not to limit the scope of thefeatures, characteristics and concepts described in the claims.Therefore, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope of the present disclosure.Therefore, the scope of the present disclosure is defined not by thedetailed description above but by the appended claims.

What is claimed is:
 1. A semiconductor device, comprising: a firsttransistor in a first region of a substrate and a second transistor in asecond region of the substrate, wherein the first transistor comprises:a first nanowire having a first channel region; a first gate electrodesurrounding the first nanowire; a first gate dielectric layer betweenthe first nanowire and the first gate electrode; a first source/drainregion connected to an edge of the first nanowire; and aninner-insulating spacer between the first gate dielectric layer and thefirst source/drain region, and the second transistor comprises: a secondnanowire having a second channel region; a second gate electrodesurrounding the second nanowire; a second gate dielectric layer betweenthe second nanowire and the second gate electrode; and a secondsource/drain region connected to an edge of the second nanowire.
 2. Thesemiconductor device of claim 1, wherein the first gate dielectric layerextends between the first gate electrode and the inner-insulatingspacer, and the second gate dielectric layer extends between the secondgate electrode and the second source/drain region.
 3. The semiconductordevice of claim 1, wherein the first source/drain region is not incontact with the first gate dielectric layer, and the secondsource/drain region is in contact with the second gate dielectric layer.4. The semiconductor device of claim 1, wherein the inner-insulatingspacer comprises a first material having a first dielectric constant,and the first gate dielectric layer and second gate dielectric layercomprise a second material having a second dielectric constant greaterthan the first dielectric constant.
 5. The semiconductor device of claim1, further comprising: a first external insulating spacer surroundingsides of the first gate electrode, wherein the first external insulatingspacer and the inner-insulating spacer overlap and are located over thesubstrate at different levels from each other in a directionperpendicular to the substrate.
 6. The semiconductor device of claim 5,wherein the first external insulating spacer and the inner-insulatingspacer comprise different materials from each other.
 7. Thesemiconductor device of claim 1, further comprising: a second externalinsulating spacer surrounding sides of the second gate electrode on thesecond nanowire, wherein the second external insulating spacer and thesecond gate electrode overlap and are located over the substrate atdifferent levels from each other in a direction perpendicular to thesubstrate.
 8. The semiconductor device of claim 1, wherein the secondsource/drain region comprises at least one protrusion portion, and theat least one protrusion portion contacts the second gate dielectriclayer.
 9. The semiconductor device of claim 1, further comprising abuffer layer extending along a main surface extension direction of thesubstrate between the substrate and the first gate electrode and betweenthe substrate and the second gate electrode, wherein the buffer layercomprises a material having a lattice constant greater than a latticeconstant of the substrate.
 10. The semiconductor device of claim 1,further comprising: a first channel separation region between thesubstrate and the first gate electrode and extending along a mainsurface extension direction of the substrate, wherein the first channelseparation region includes a conductive type dopant different from thatof the first source/drain region; and a second channel separation regionbetween the substrate and the second gate electrode and extending alongthe main surface extension direction of the substrate, wherein thesecond channel separation region includes a conductive type dopantdifferent from that of the second source/drain region.
 11. Thesemiconductor device of claim 1, wherein the first transistor is ann-type metal-oxide-semiconductor (NMOS) transistor, and the secondtransistor is a p-type metal-oxide-semiconductor (PMOS) transistor. 12.A semiconductor device, comprising: a first transistor in a first regionof a substrate and a second transistor in a second region of thesubstrate, wherein the first transistor comprises: a plurality of firstnanowires having a plurality of first channel regions; a first gateelectrode surrounding the plurality of first nanowires; a first gatedielectric layer between the plurality of first nanowires and the firstgate electrode; a first source/drain region connected to an edge of theplurality of first nanowires; and an inner-insulating spacer between thefirst gate dielectric layer and the first source/drain region, and thesecond transistor comprises: a plurality of second nanowires having aplurality of second channel regions; a second gate electrode surroundingthe plurality of second nanowires; a second gate dielectric layerbetween the plurality of second nanowires and the second gate electrode;and a second source/drain region connected to an edge of the pluralityof second nanowires.
 13. The semiconductor device of claim 12, whereinthe first gate dielectric layer extends between the first gate electrodeand the inner-insulating spacer, and the second gate dielectric layerextends between the second gate electrode and the second source/drainregion.
 14. The semiconductor device of claim 12, wherein the firstsource/drain region is not in contact with the first gate dielectriclayer, and the second source/drain region is in contact with the secondgate dielectric layer.
 15. The semiconductor device of claim 12, furthercomprising: a first external insulating spacer surrounding sides of thefirst gate electrode on the plurality of first nanowires; and a secondexternal insulating spacer surrounding sides of the second gateelectrode on the plurality of second nanowires, wherein the firstexternal insulating spacer and the inner-insulating spacer overlap andare located at different levels from each other over the substrate in adirection perpendicular to the substrate, and the second externalinsulating spacer and the second gate electrode overlap and are locatedat different levels from each other over the substrate in a directionperpendicular to the substrate.
 16. A semiconductor device, comprising:a substrate with a first region and a second region; a first transistorin the first region of the substrate and comprising a first nanowire, afirst gate electrode surrounding the first nanowire, a first gatedielectric layer, a first source region, a first drain region, and aninner-insulating spacer, and a second transistor in the second region ofthe substrate comprising a second nanowire, a second gate electrodesurrounding the second nanowire, a second gate dielectric layer, asecond source region and a second drain region, wherein the first gatedielectric layer is provided between the first nanowire and the firstgate electrode, and between the inner-insulating spacer and the firstgate electrode, wherein the inner-insulating spacer maintains a spacebetween the first gate dielectric layer and the first source region andthe first drain region, wherein the second gate dielectric layer isprovided between the second nanowire and the second gate electrode,between the second source region and the second gate electrode, andbetween the second drain region and the second gate electrode.
 17. Thesemiconductor device of claim 16, wherein the first source region andfirst drain region are not in contact with the first gate dielectriclayer, and wherein the second source region and second drain region arein contact with the second gate dielectric layer.
 18. The semiconductordevice of claim 16, further comprising: a first external insulatingspacer laterally surrounding the first gate electrode on a side of thefirst nanowire opposite from the inner-insulating spacer and from thesubstrate, and a second external insulating spacer laterally surroundingthe second gate electrode on a side of the second nanowire opposite fromthe substrate.
 19. The semiconductor device of claim 16, wherein thefirst nanowire channels electrons between the first source region andthe first drain region, and the second nanowire channels holes betweenthe second source region and the second drain region.
 20. Thesemiconductor device of claim 16, wherein the first transistor comprisesat least one third nanowire that channels electrons between the firstsource region and the first drain region and that is surrounded by thefirst gate electrode, wherein the first gate dielectric layer isprovided between each of the first nanowire and the at least one thirdnanowires and the first gate electrode, wherein the inner-insulatingspacer is provided between each of the first nanowire and thirdnanowires in a direction perpendicular to the substrate, wherein thesecond transistor comprises at least one fourth nanowire that channelsholes between the second source region and the second drain region andthat is surrounded by the second gate electrode, and wherein the secondgate dielectric layer is provided between each of the second nanowireand the at least one fourth nanowires and the second gate electrode.